Trying to get the year out of a date with sed

Question

I'm using the following command to get the year out of a string using sed.

echo 1234-1-12 | sed -r 's/(\d{4})-\d{1,2}-\d{1,2}/\1/'

but somehow it returns the entire date instead of the year.

getting 1234-1-12

expecting 1234

Any ideas why it doesn't work?

Answer 1

Simple grep approach:

echo "1234-1-12" | grep -o '^[^-]*'

The output:

1234

Answer 2

Use the date command:

string="1234-1-12"
date -d "${string}" +%Y

Output:

1234